Rationale Behind Essay Scores: Enhancing S-LLM's Multi-Trait Essay Scoring with Rationale Generated by LLMs

Existing automated essay scoring (AES) has solely relied on essay text without using explanatory rationales for the scores, thereby forgoing an opportunity to capture the specific aspects evaluated by rubric indicators in a fine-grained manner. This paper introduces Rationale-based Multiple Trait Scoring (RMTS), a novel approach for multi-trait essay scoring that integrates prompt-engineering-based large language models (LLMs) with a fine-tuning-based essay scoring model using a smaller large language model (S-LLM). RMTS uses an LLM-based trait-wise rationale generation system where a separate LLM agent generates trait-specific rationales based on rubric guidelines, which the scoring model uses to accurately predict multi-trait scores. Extensive experiments on benchmark datasets, including ASAP, ASAP++, and Feedback Prize, show that RMTS significantly outperforms state-of-the-art models and vanilla S-LLMs in trait-specific scoring. By assisting quantitative assessment with fine-grained qualitative rationales, RMTS enhances the trait-wise reliability, providing partial explanations about essays.

Beyond Right and Wrong: Mitigating Cold Start in Knowledge Tracing Using Large Language Model and Option Weight

Knowledge Tracing (KT) is vital in educational data mining, enabling personalized learning by tracking learners' knowledge states and forecasting their academic outcomes. This study introduces the LOKT (Large Language Model Option-weighted Knowledge Tracing) model to address the cold start problem where limited historical data available using large language models (LLMs). While traditional KT models have incorporated option weights, our research extends this by integrating these weights into an LLM-based KT framework. Moving beyond the binary classification of correct and incorrect responses, we emphasize that different types of incorrect answers offer valuable insights into a learner's knowledge state. By converting these responses into text-based ordinal categories, we enable LLMs to assess learner understanding with greater clarity, although our approach focuses on the final knowledge state rather than the progression of learning over time. Using five public datasets, we demonstrate that the LOKT model sustains high predictive accuracy even with limited data, effectively addressing both "learner cold-start" and "system cold-start" scenarios. These findings showcase LOKT's potential to enhance LLM-based learning tools and support early-stage personalization.

PreMix: Boosting Multiple Instance Learning in Digital Histopathology through Pre-training with Intra-Batch Slide Mixing

The classification of gigapixel-sized whole slide images (WSIs), digital representations of histological slides obtained via a high-resolution scanner, faces significant challenges associated with the meticulous and time-consuming nature of fine-grained labeling. While weakly-supervised multiple instance learning (MIL) has emerged as a promising approach, current MIL methods are constrained by their limited ability to leverage the wealth of information embedded within unlabeled WSIs. This limitation often necessitates training MIL feature aggregators from scratch after the feature extraction process, hindering efficiency and accuracy. PreMix extends the general MIL framework by pre-training the MIL aggregator with an intra-batch slide mixing approach. Specifically, PreMix incorporates Barlow Twins Slide Mixing during pre-training, enhancing its ability to handle diverse WSI sizes and maximizing the utility of unlabeled WSIs. Combined with Mixup and Manifold Mixup during fine-tuning, PreMix achieves a mean of 4.7% performance improvement over the baseline MIL framework, the hierarchical image pyramid transformer (HIPT), on the Camelyon16 dataset. The observed improvement across a range of active learning acquisition functions and WSI-labeled training budgets highlights the framework's adaptability to diverse datasets and varying resource constraints. Ultimately, PreMix paves the way for more efficient and accurate WSI classification under limited WSI-labeled datasets, encouraging the broader adoption of unlabeled WSI data in histopathological research. The code is available at https://anonymous.4open.science/r/PreMix

Rethinking Pre-trained Feature Extractor Selection in Multiple Instance Learning for Whole Slide Image Classification

Multiple instance learning (MIL) has become a preferred method for classifying gigapixel whole slide images (WSIs), without requiring patch label annotation. The focus of the current MIL research stream is on the embedding-based MIL approach, which involves extracting feature vectors from patches using a pre-trained feature extractor. These feature vectors are then fed into an MIL aggregator for slide-level prediction. Despite prior research suggestions on enhancing the most commonly used ResNet50 supervised model pre-trained on ImageNet-1K, there remains a lack of clear guidance on selecting the optimal feature extractor to maximize WSI performance. This study aims at addressing this gap by examining MIL feature extractors across three dimensions: pre-training dataset, backbone model, and pre-training method. Extensive experiments were carried out on the two public WSI datasets (TCGA-NSCLC and Camelyon16) using four SOTA MIL models. The main findings indicate the following: 1) Performance significantly improves with larger and more varied pre-training datasets in both CNN and Transformer backbones. 2) `Modern and deeper' backbones greatly outperform `standard' backbones (ResNet and ViT), with performance improvements more guaranteed in Transformer-based backbones. 3) The choice of self-supervised learning (SSL) method is crucial, with the most significant benefits observed when applied to the Transformer (ViT) backbone. The study findings have practical implications, including designing more effective pathological foundation models. Our code is available at: https://anonymous.4open.science/r/MIL-Feature-Extractor-Selection

MicroMIL: Graph-based Contextual Multiple Instance Learning for Patient Diagnosis Using Microscopy Images

Current histopathology research has primarily focused on using whole-slide images (WSIs) produced by scanners with weakly-supervised multiple instance learning (MIL). However, WSIs are costly, memory-intensive, and require extensive analysis time. As an alternative, microscopy-based analysis offers cost and memory efficiency, though microscopy images face issues with unknown absolute positions and redundant images due to multiple captures from the subjective perspectives of pathologists. To this end, we introduce MicroMIL, a weakly-supervised MIL framework specifically built to address these challenges by dynamically clustering images using deep cluster embedding (DCE) and Gumbel Softmax for representative image extraction. Graph edges are then constructed from the upper triangular similarity matrix, with nodes connected to their most similar neighbors, and a graph neural network (GNN) is utilized to capture local and diverse areas of contextual information. Unlike existing graph-based MIL methods designed for WSIs that require absolute positions, MicroMIL efficiently handles the graph edges without this need. Extensive evaluations on real-world colon cancer (Seegene) and public BreakHis datasets demonstrate that MicroMIL outperforms state-of-the-art (SOTA) methods, offering a robust and efficient solution for patient diagnosis using microscopy images. The code is available at https://anonymous.4open.science/r/MicroMIL-6C7C

Leveraging Multi-facet Paths for Heterogeneous Graph Representation Learning

Recent advancements in graph neural networks (GNNs) and heterogeneous GNNs (HGNNs) have advanced node embeddings and relationship learning for various tasks. However, existing methods often rely on domain-specific predefined meta-paths, which are coarse-grained and focus solely on aspects like node type, limiting their ability to capture complex interactions. We introduce MF2Vec, a model that uses multi-faceted (fine-grained) paths instead of predefined meta-paths. MF2Vec extracts paths via random walks and generates multi-faceted vectors, ignoring predefined schemas. This method learns diverse aspects of nodes and their relationships, constructs a homogeneous network, and creates node embeddings for classification, link prediction, and clustering. Extensive experiments show that MF2Vec outperforms existing methods, offering a more flexible and comprehensive framework for analyzing complex networks. The code is available at https://anonymous.4open.science/r/MF2Vec-6ABC.